types: fix lint warnings

src/ProgressBar.ts

@@ -94,7 +94,7 @@ export class ProgressBar implements Required<Omit<IProgressBarOptions, 'current'
 
   #current = Progress.Start;
   #end: number | undefined;
-  #start = new Date().getTime();
+  readonly #start = new Date().getTime();
   #status = TaskStatus.Pending;
   #tokens: Map<TemplateToken | string, string> = new Map();
 

src/Task.ts

@@ -23,15 +23,15 @@ export interface ITaskOptions {
 
 /** Entity for managing a task - includes all child objects (informational messages, errors, progress bars, and tasks) */
 export class Task {
-  #autoClear: boolean;
+  readonly #autoClear: boolean;
   #bars: ProgressBar[] = [];
-  #errors: string[] = [];
-  #id: number;
-  #logs = new Set<string>();
+  readonly #errors: string[] = [];
+  readonly #id: number;
+  readonly #logs = new Set<string>();
   #status: TaskStatus;
   #subtasks: Task[] = [];
   #text: string;
-  #warnings = new Set<string>();
+  readonly #warnings = new Set<string>();
 
   constructor(text: string, { status, autoClear }: ITaskOptions = {}) {
     this.#id = ++uid;

src/TaskTree.ts

@@ -22,13 +22,13 @@ export class TaskTree {
 
   #autoClear = false;
   #handle: NodeJS.Timeout | undefined;
-  #manager: UpdateManager;
+  readonly #manager: UpdateManager;
   #offset = 0;
   #paused = false;
   #silent = false;
   #started = false;
   #tasks: Task[];
-  #theme: Theme;
+  readonly #theme: Theme;
 
   private constructor(theme?: ThemeOptions) {
     this.#tasks = [];

src/Theme.ts

@@ -68,9 +68,9 @@ export type ThemeOptions = {
 export class Theme {
   static INDENT = '  ';
 
-  #badges: Map<IndicationType, string> = new Map();
-  #colors: Map<IndicationType, string> = new Map();
-  #symbols: Map<IndicationType, string> = new Map();
+  readonly #badges: Map<IndicationType, string> = new Map();
+  readonly #colors: Map<IndicationType, string> = new Map();
+  readonly #symbols: Map<IndicationType, string> = new Map();
 
   constructor(options?: ThemeOptions) {
     if (options) {